(1) Field of the Invention
The invention relates to a process for fabricating a semiconductor field emission device, and more particularly to a method for manufacturing such a device in a sealed vacuum.
(2) Description of the Related Art
Field emission devices have received increased attention in recent years, as integrated circuit manufacturing techniques have allowed for further miniaturization and, subsequently, new applications. Typically, one or many of a small, conical conductive emitter tip are formed on a conductive cathode. A second conductive surface, or grid, is formed in close proximity and parallel to the cathode surface, with the two surfaces separated by a dielectric layer. Apertures are formed in the grid layer and dielectric in the area of the emitter tips, with the grid opening surrounding the upper part of the emitter. An anode is mounted opposite the grid and a vacuum formed in the region between the emission device and anode, to allow for electron emission. When a positive bias is applied at the grid with respect to the cathode, electrons are emitted from the small emitter tip, with the current generated depending on the operating voltage, the sharpness of the tip and the emitter material work function.
A sealed vacuum electronic device is described in IEDM 91'8.3.1., but is difficult to manufacture. There are several methods for fabricating field emission devices such as in U.S. Pat. No. 4,857,799 to C. A. Spindt et al, and U.S. Pat. No. 4,908,539 to Meyer. Spindt describes the manufacturing of field emission devices for matrix-addressed flat panel displays, and resolves one earlier problem of screen distortion due to the vacuum by providing a support structure between the grid and anode at intermittent locations across the display surface. Details on how the vacuum is created are not provided, however.